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1、第32卷第11期高电压技术Vol.32No.112006年11月HighVoltageEngineeringNov.2006#103#*基于独立光伏系统的三相三电平逆变器张建功,刘邦银,段善旭,康勇(华中科技大学,武汉430074)摘要:为给二级能量变换结构的光伏电厂提供高效后级逆变器,设计和实现了一台12kVA逆变器。主电路采用中点位式三电平结构,以IGBT作为主开关器件,以重复控制与瞬时值反馈控制相结合的控制策略产生SPWM波,利用重复控制抑制非线形负载下的电压畸变,利用瞬时值反馈控制改善系统的动态响应过程,输出级采用LC滤波器减少输出电压u的谐波及du/dt,采用软硬件
2、相结合的限流保护方法。装置实验表明,这种逆变器效率和输出波形质量高。关键词:光伏系统;三电平逆变器;SPWM调制;重复控制;瞬时值反馈控制中图分类号:TM464文献标识码:A文章编号:1003-6520(2006)11-0103-04Three-phaseThree-levelInverterBasedonStand-alonePhotovoltanicSystemZHANGJiangong,LIUBangyin,DUANShanxu,KANGYong(HuazhongUniversityofScienceandTechnology,Wuhan430074,China)Abs
3、tract:Solarenergyisoneofthemostcleanandrichsourceinnature,almostallstatesmaketheirbestendeavorstoexploititandbuildmanyphotovoltaicplants,theinverterisanimportantingredientofthePVsystem,highqua-lityoutputvoltagewaveformisrequiredfortheinverter,thedesignandimplementationofa12kVAinverterapplie
4、dtostand-alonePVsystemisproposedinthispaper.Themaincircuitstructureoftheinverterisbasedonneutralpointclampedthree-levelinverterusingIGBT,Thetriggerimpulsesequencetoeachoftheinverterbridgearmsisgivenaloneanditsphasecontrastis120degreetoimplementmult-imodelsupply.Theamplitudefrequencycharac-t
5、eristicofthecontrolledobjectisdrawnbyexperimentanditsmathematicmodelisderivedwiththeloadcurrenttreatedasameasurabledisturbanceinput.Toachievenearlysinusoidaloutputvoltageevenwithnonlinearloadsandabruptloadvariation,theSPWMmodulationbasedonrepetitivecontrolandinstantaneousfeedbackcontrolisem
6、-ployedfortheinverter,repetitivecontrolisusedtoreducevoltagedistortionundernonlinearloads,andinstantane-ouscontrolisdesignedtoquickenthedynamicresponseprocessunderabruptloadvariation,thecontrollerparameterisdesignedandobtainedbyMATLAB.Theoutputharmonicsanddv/dtisdepressedbyLCfilter,thecurre
7、nt-limit-edmethodcombiningsoftwarewithhardwareisadopted.Varioustestshaveprovedveracityofthecontrolledobject,rationalityofthecontrollerparameter,thehighlevelofoutputvoltagewaveformqualityandefficiencyoftheinsta-llation.Keywords:photovoltanicsystem;three-l